How to Build a PC in 2018: Choosing the Right Components

When we write about the PC market at ExtremeTech, it’s almost always from the DIY or enthusiast perspective. But we don’t actually talk much about that most basic of tasks — how to build a PC. The actual assembly process isn’t usually all that difficult, but choosing the right components can be tricky. Let’s talk about it.

Note: Because this is meant to serve as a general purchase guide, rather than a specific “Here’s a great Intel or AMD system,” I’ve kept the recommendations general and intended to suit an audience unsure where to start pulling together data on the topic. Questions on peripherals like mice and keyboards are also beyond the scope of this article.

Case

While components like the CPU and GPU will determine what your machine can do in an absolute sense, which chassis you pick is still important. The PC case (See on Amazon) determines what kinds of CPUs and GPUs you can install, what your peripheral and storage options are, and what cooling equipment can be installed. You may not plan to open it often or to change the installed equipment, but every interaction you have with your system will literally happen through and around the case it uses.

A Dell mini-tower. Note the small number of rear slots.

Cases tend to be marketed as one of several types of tower — full tower, mid tower, and mini tower are the three basic categories, along with a few for literal “desktop” machines (HTPC). There’s overlap between case and motherboard sizes, so I’ll address that question more fully later on. Small cases are typically harder to work in, both because they give you less room to maneuver when installing or removing components and because you may have to install hardware in a specific order. There are towers, for example, that allow you to access the rear of the motherboard to remove a bolted-on heatsink without having to pull the entire motherboard to do it. An HTPC case isn’t going to offer that kind of benefit.

The other advantage of larger cases, if I’m being honest, is that they let you be lazier. Need to install a new SSD or HDD, and don’t feel like taking the old one out? No problem. Leave it right where it is. There’s usually not much difference in connectivity — small PCs can rival large ones when it comes to USB ports and other peripheral options, if they’re designed to do it.

Cooling

PC cooling options range from the heatsinks AMD and Intel ship with their own boxed processors to various esoteric multi-stage freon units and fanless oil immersion rigs. Most enthusiasts opt for more prosaic air cooling methods.

The typical CPU coolers (See on Amazon) from AMD and Nvidia will absolutely keep your CPU within normal operating temperatures and running fine, even under load. You don’t need to spend money on an aftermarket cooler at all, if you don’t want to. If you do buy an aftermarket cooler, make sure to check its intended motherboard orientation, maximum cooler height (if installing it into a smaller chassis) and whether it makes installing RAM difficult. This last is a common issue; many aftermarket CPU coolers partially overhang RAM sockets when installed. Since most RAM these days has heatsinks of its own, this can make installing or swapping RAM challenging.

The Noctua DH15. This is a high-end cooler (most are not this large and don’t use dual fans).

If I had to pick one CPU cooler brand to recommend, it’d be Noctua. Noctua coolers aren’t particularly cheap, but they come with extensive, full-color instructions, include installation hardware like screwdrivers, the build quality of their fans and heatsinks is excellent, and they offer an excellent upgrade policy.

A Noctua NH-U14S, installed. Note the way the cooler overhangs the RAM slots. Image by Sebastian Anthony.

If you have an older cooler, in many cases, Noctua offers upgrade kits that will allow you to keep using it on a newer motherboard. Given that CPUs have topped out at roughly 140W (with a handful of exceptions) for a decade, this is a great way to keep using a valuable component that can cool a newer chip just as well as an old one.

Note: CPU coolers are typically rated in terms of their TDP, or Thermal Design Power. This is the amount of heat the cooler is designed to dissipate over a given period of time and should be matched to the listed TDP of the CPU at minimum. It’s fine to use a cooler that can handle a 150W TDP on a 50W chip, but don’t try using a 50W cooler on a 150W CPU. It won’t fry — we’re a bit past that point now — but the system may destabilize and will run slowly.

Motherboard

The motherboard you pick shapes what your system is capable of and how much expandability you can expect in the future. There are three basic motherboard types in the consumer market, in order of size: Mini-ITX, Micro-ATX (mATX), and ATX.

ATX motherboards (See on Amazon) are full-sized standard consumer products, with a typical seven expansion slots. mATX boards are shorter and offer fewer slots, while ITX boards have the fewest expansion and memory slots of all. If you’re not sure which you want, consider this: Most users won’t notice the difference between an ATX versus an mATX board as far as useful onboard features or capabilities, while an ITX board does require various meaningful tradeoffs even on low-level features.

A decent rule of thumb: If you know you need a Mini-ITX board for a specific project, that’s one thing, but you’ll probably want something larger for any general use system.

As you shop for a case, you’ll see them labeled “ATX Full Tower,” “ATX Mid-Tower,” etc. Any chassis labeled ATX should be capable of handling a full-size ATX motherboard. Each case should specifically state which motherboard form factors it supports, including workstation motherboard standards like EATX that we’re not discussing here.

The difference between an ATX Full Tower and an ATX mini tower, if both support a full-sized ATX motherboard, will be the height and clearance within the case itself. Your GPU and cooler options may be constrained if you opt for a small tower, even if the motherboard itself always fits into the available space.

CPU

CPUs fit into sockets on motherboards, which means the motherboard has to have the appropriate number of pins (or holes, in AMD’s case). This is commonly referred to as a socket standard. Intel’s current socket standard is LGA1151, while AMD’s is Socket AM4.

The combination of the CPU and motherboard you choose determines your RAM type. We have to say “in combination,” because in some cases, CPUs (See on Amazon) have supported multiple types of DRAM, which meant which standard you used was a question of which your motherboard supported. Generally speaking, the motherboard box will tell you which is which, and given that DDR3 is on its way out, DDR4 should be the only solution you really have to worry about as far as DRAM is concerned. Whether you’ll be able to afford DRAM is another question.

Past the question of socket compatibility, which CPU you choose has knock-on effects on the rest of the system build. Higher-end CPUs typically draw more power and you may want to use a better cooler with top-end models. Always make sure to match your CPUs listed TDP with the TDP of the cooler you are using (CPUs shipped from AMD and Intel will come with an appropriately rated CPU cooler if you buy retail packaged parts).

GPU

GPU prices are currently so over-inflated, my honest advice is not to buy a GPU at all and make do with whatever you’ve already got, buy used, or otherwise limp along until the cryptocurrency market calms the hell down.

Apart from that minor problem, the two big GPU issues to be aware of are the physical size of the card and its overall power consumption. GPUs (See on Amazon) are typically defined in terms of the number of slots they take up inside the chassis and the physical length of the card. Dual-slot cards are now the norm across most of the market, since this design allows for larger, quieter coolers, but this also means you need a certain minimum footprint within your case.

When picking out a motherboard you’ll want to account for this. If you scroll up and look at our picture of the various motherboard form factors, you’ll see a huge gap between the first and second full-length PCI Express slots. Not all boards use this layout style, but it’s a useful way to illustrate this issue. In this case, the motherboard manufacturer has chosen to space the first slots out, to allow for a double-sized cooler for each of two GPUs.

The Radeon R9 295X2. Currently the longest GPU I’m aware of, at over 12 inches.

The other physical constraint to be aware of when buying a GPU is length — and this plays into what kind of chassis you buy. Any ATX chassis should hold an ATX motherboard, but ATX motherboards are only 9.6 inches wide. Because some smaller chassis allow the drive bays to partially overlap the motherboard tray, you can wind up with a case that has less than 9.6-inches of room for a GPU, even though the case itself claims compliance with the ATX standard.

The longest GPU I’m aware of is the Radeon R9 295X2 (pictured above), at 307mm (12.08 inches). Most consumer cards are shorter than this, but always check the length of your GPU model against the internal width of the motherboard tray.

Power Supply

When choosing a power supply, you’ll need to pay attention to several aspects of the situation. First, the PSU (See on Amazon) needs to provide sufficient power for all the components in the system, with some additional room on top for a safety margin. Sites like Newegg have their own power supply calculators, with varying degrees of complexity depending on how far down this particular rabbit hole you want to jump. Generally speaking, 300W will run a desktop without a GPU, 550W will handle a midrange GPU or below, and a high-end GPU needs at least six hundred watts.

Second, consider the number of six or eight-pin plugs for powering GPUs. Two eight-pin plugs (or one six-pin/eight-pin combo) will drive a single GPU, while four or more may be needed for multi-GPU configurations. Again, don’t assume that more plugs means the power supply can feed whatever GPU you’re considering — the wattage and pinouts both need to match the card. The PSU also needs to provide enough power over the 12V rails for a high-end GPU, though this shouldn’t be an issue for any single GPU system provided you follow the advice above.

Third, consider whether you want an 80 Plus unit or something that offers a higher level of overall power efficiency. This article should offer some additional context for that decision and some general power consumption advice.

Final point: Do not buy a generic power supply from a no-name vendor. I cannot, cannot, cannot stress this enough. Gallons of ink have been spilled on this point and they all point in the same direction. Generic PSUs from no-name vendors will die at less than half the load they claim to rate, more often than not. Do not do this. Do not. Skimp everywhere and anywhere else, but do not skimp here.

RAM

RAM prices (See on Amazon) are also currently high and may remain that way through the end of 2018. DDR4 is the mainstream memory currently on the market (unless you know you need older DDR3, DDR4 is what you’ll likely be buying), but given the current pricing, it’s hard to recommend splurging.

You’ll want to deploy RAM in matched sticks in virtually all cases, but right now our advice is to price for affordable capacity first. See our piece on RAM pricing and affordability in 2018 for more details here.

Storage

For storage you have two choices — larger, but much slower hard drives, or faster and smaller SSDs. Generally speaking, an SSD (See on Amazon) will always be the better option, though some users hybridize and use both, with a moderate-sized SSD as a boot drive and preferred application installation platform (256GB or 512GB) and a larger (2TB to 4TB+) data storage partition. Media files and other resources can typically be kept on an old-fashioned spinning disk.

SSDs based on the M.2 standard that interface via PCI Express are also available. These are faster than traditional SSDs, which use SATA (so do HDDs) but require motherboard support. If you are interested in an M.2 PCI Express SSD, make certain your motherboard has the appropriate slot and level of support. (More information on SSDs and how they function can be found here.)

If you want to include a Blu-ray drive in your build you certainly can, provided you pick a case that supports one. Optical media playback isn’t as central to PCs as it was 10 years ago, but the option exists and you can avail yourself of it. Be advised you’ll need a third-party Blu-ray playback solution (CyberLink PowerDVD is pretty much the go-to here).

Those are the major components of a typical PC build, apart from specialty cases like sound cards (you probably don’t need one). Questions? Comments? Sound off below.